Now that NCAA soccer season is just around the corner, i'm looking to get a better lens to go with my D300. I'm shooting mainly for the school newspaper, but also for fun in general. I use a 18-70mm and a 28-300mm lens at the moment, but i'm really looking for a better performer for sports. On top of that I would love to do more Macro shots, so if i could get one that would be able to do both well, i would be a happy camper.

I have been shooting football, and rugby games for my local paper for about a year or so, I have the simplest lens as you can see I would personally go for a faster 300mm if not just a 200mm 2.8. If you have had a little experience and can crop like a champ then those are just as easy to use as the 28-300 you got now. Personally I would keep the 28-300mm and save for a better faster bigger zoom lens. IMO.

Depends on the sport and the body you have,and what kind of shots you're after. Probably the most useful is a 70-200 f/2.8 with ultrasonic motor focusing, for fast focusing and lots of different framing options in one lens. However, don't forget wide-angle shots that show some setting, some of the stadium, some of the surroundings.
Primes of 20,24,35,50mm can be used to good effect indoors on court sports. The 85mm 1.8 is pretty useful, as is a 100 or 105mm f/2 or 135mm f/2.

The 200mm/2 is the fastest-focusing prime, but is also a bear to handle. The 300/2.8 handles easier and is very useful for many things. The 300/4 is nice for bright-weather shooting,and is lightweight. You can use "almost any lens" to get good shots, if you have a plan, and work within the limitations of your gear.

If you have the money for only "ONE" lens however, I'd say it ought to be the 85mm f/1.8 as an all-around lens that will work to bring home good shots of a lot of sports, indoors and out, and which will not break the bank. Not all football needs to be frame-filling, half-body-only-blow-nout-background 400mm stuff; there are plenty of basketball,volleyball,wrestling,track and field, and football shots that can be made with a quality 85mm prime that costs under $375.

For soccer, I often use my Sigma 100-300 f/4 on one body and 28=70 on a second body.

Any zoom lens with "macro" in the title is effectively a marketing move to show that the lens has closer focusing than most. At best they get to around half lifesize (1:2) which is half of what a true macro lens can achieve in magnification (which is 1:1). This makes them good for flowers and similar larger subjects, but no good for flies or smaller insects or subjects.

I think that you first need to decide upon a budget for yourself - there are big differences in the gear you can get - at the cheapest end you could get a sigma 70-300mm f4-5.6 APO macro whilst at the more expensive you can get a setup like GSgarry mentions.
There are also many setups that fall in the middle of those price points. So we need an idea of budget in order to give you the best advice possible.

I posted another thread (it is more directly aimed at experiences with certain lenses, which was the reason i started a new thread) clarifying my budget and the situation I'm in now (lost a job, then got another!) so the money will start coming in soon. As i mentioned in the other post, I will have a budget of around $800 in a few months if my budget goes as planned. (Mens Basketball starts in November, so thats when I have till essentially) Correct me if I'm wrong, but a prime lens will generally produce sharper images than a zoom? That is why I am leaning towards a prime. I currently use a 28-300 and a 18-70, both of which are kit lenses . Hopefully the new information can help ya'll help me!